Process for recovering the vapors of volatile liquids.



y KJE. BARTH.'l y PROCESS FOR RECOVERING THE VAPORS 0F V-LATILE LIQUIDS.y

APPLICATION FILED APR. 7. |914. l 1,264,479. PatentedApn 30, 15H8.

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PROCES@ FOIE RECOVEBING THE VAPOBS 0F VOLATILE LQUIISS.

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Patented Apr. 30, 105m.

Application led April 7, 1914. Serial No, 830,100.

To all whom it may concern.' Be it known that l, Kuur EMIL BARTH, a citizen of the German Empire, and resident o' Charlottenburg, Germany, have invented certain new and useful Improvementsin Frbcesses for Recovering the Vapore of Volatile Liquids, of which thefollowing is a specication.

. When mlene, kerosene, or the like is stored in a(large tanks, the upper portion of the'tank, above the level of the inflammable liquid, is iilled either with-atmospheric air or with a non-oxidizable protecting gas introduced into the tank for this purpose. ln the course of time this air or as becomes saturated with vapors of the inflammable and when the tank is iilled anew, the air or gas, laden with vapors, and therefore often of an explosive character, escapes into the surrounding air, entailing a loss of the valuable vapors of the iniammable Upon attempting to recover these vapors by cooling them with water, say to 15 centigrade (this bein lthe average'temperature it is found that only a very small portion of the inflammable liquid y will be condensed. Owing to the fact that the gases generally are not fully saturated with vapors of the inflammable liquid when the air'has a .temperature ot' say 30 centigrade, the major portion of such vapors will not condense until the temperature falls below the dew point of the mixture of gas and vapors.

According to my present invention, a very 'Wir-ibut recovery of the vapors of the infiammanie liquid is obtained by first cooling the mixture of gas and vapors by ordinary ajrcooling or water-cooling, and then cooling to a still lower temperature, by means orv articial refrigerating agents, preferablyto or below 0 centigrade. Only by this additional cooling does it become possible to recover by condensation, the mayor portion of the vapors contained in the air or gas above the liquid. The complete recovery of these vapors could be obtained only by cooling to an exceedingly low temperature (as low as' 273 centi grade below zero), which of course process. In view of the fact that in practice t ing is continued only to about 0 centigrade,

a small proportion of vapors still remains 'in below the lowest explosion limit, so that there f will be no danger of the gas mixtures erplodlng when it is allowed toescapc into i the surrounding air.

For `the sake of an economical operation, the process, when carried out in connection with gasolene tanks, for example?, consists` in first cooling the mixture of air and gasolene vapors to about 15, -centigrade in a water cooler, and then to about 0 centigrade in another cooler employing artiiicially refrigerated salt solutions, whereby as large f a proportion of gasolene vapors aspossibie is separated and reeoveredby condensation. Since the mixture of gasolene vapors and air `which leaves the second cooler at a temy erature oi' ab0ut0 centigrade, is lstill withM in explosive limits, such mixture, according ves fix

to my invention, before it is allowedto escape into the surrounding air, receives an addition of air or of a non-oxidizable gas so as to dilute it to a point below the lower explosion limit and thus render it absolutely safe.

Experiments have shown that in the ease of fully saturated mixtures of4 air and gasolcne vapors, at a tcniperatnre'of 30 centigrade, about 73% of the total amount of gasolene vapors' can be separated and recovered by cooling to a 'temperature of 0 centigradi?, about 2/3 of this amount being recovered during the first* stage, when the' mixture is cooled by water from 30 to about 15 Centigrade, while the remainino l, is recovered during the second stage, when the eoolino' from 15 to 0 centigrade is etfectedtby means of brine or other artificially cooled salt solutions. Of course, if the inintu're of air and gasolene vapors is not saturated, the proportions of recovery during the two stages will be diei'ent from the figures given. above.

ln the accompanying drawings I have illustrated, in a diagrammatic vertical sec tion, anexample of an apparatus for carryingout my invention. t

rom lthe .Lgasolene 4storage tank (not shown) a pipe 1 lconveys the mixture of air andvapor mixture tothe upper portion of.

a cooler' 2, which lmay be constructed as shown, comprisin' pipes through which the gaseous' mixture ows, while cooling Water circulates around the pipes. From the lower part of the cooler-2 'a conduit 3 leads to the upper' portion of a tubular cooler 4, through the pipes of -which the gaseous mixture flows, while around the pipes circulates the -brine or other cooling medilfm artificially refrigerated Iin a'machine of any usual or approved'type.

' The cdnduit' 5 leading from the lower part of the cooler 4 terminates in the cover of a receptacle 6 serving as a liquidseal, said receptacle being provided at its central .por-- tion with a depending partition 8 dipping intol the liquid 7 o r instance,b water).r While the conduit 5 connects with the vcom-y Y pertinent at the left 'of the partition 8, the compartment at the' right of said partition communicates with the conduit 9 which leads from the @diver ofthe receptacle 6 to the surround-ing air. With Athe lower portion of theA nduit 9, above the receptacle ,6, is connected the pressure pipe-or delivery pipe 10 of a blower 11..

The gasolene deposited in the lower portions of the coolers 2 and 4 is conveyed through'/ the conduits 12 and 13 respectively into the underground collector 14, from whichit may be withdrawn through pipe 15.

After thev mixture of air and gasoleneyapors has been deprived of the major portion of its gasolene vapor contents 1n the coolers 2 and 4, it passesthrough the liquidseal 6,

"Y, ,8 into the conduit 9.- In the lower por- "tion othis conduit, air or a non-oxidizable is injected by the blower 11 by way of effe 1,264,479

the delivery pipe 10, thereby dilutingthe remainder of the air and vapor mixture to such an extent as to bring it'below the lower explosion limit for mixtures of air-and gasolene vapors. The resulting harmless, that 1s t0 say, non-explosive mixture, may then vsafely be -allowed to escape into the surrounding air through the conduit 9.

The partition 8 of the receptacle 6 should dip into the liquid 7 to such a depth that when the storage tank connected with the pipe 1 is emptied, air may enter the` recovery plant so that a vacuum will not be produced in said tank.

Various modifications may belnade Without departing lfrom the nature of my invention as set forth in the appended claims.

1. The process of recovering vapors of inammable liquids from gaseous mixtures containing such vapors, which consists in first cooling said mixture to about ordinary atmospheric temperature, then further coling to a temperature materially below ordinary atmospheric temperature, separating the liquid resulting `from condensation, and diluting lthe. remainder of the mixture with a suitable gaseous agent to render it non explosive before its escape into the surrounding air.

2. The process of recovering vapors of iniammable liquids from gaseous mixtures containing such vapors, which 'consists in cooling said mixtureso as to condense said vapors, separating the condensation product, and diluting the remainder of the mixture with a suitable gaseous agentto insure its non-explosiveness. l

In testimony whereol have signed this specication in the presence of two subscrib- Witnesses HENRY H Asrnn, WOLDEMAR HAUPT. 

